A planetary gearset of the aforementioned type is suitable for the power transfer in the multi-Mega-Watt range, wherein a slow rotary motion of a drive shaft is converted to a fast rotary motion of a gearset output shaft. At least on one planetary pin, the planetary gearset can have a bearing apparatus for rotatably mounting a planet gear. The bearing apparatus can comprise at least two roller bearings that are disposed between the planet gear and the planetary pin; for example, cylindrical roller bearings or tapered roller bearings, wherein the at least two roller bearings each include an inner ring and optionally an outer ring. The inner ring can be connected in an antitorque manner with the planetary pin, and the outer ring can be connected in an antitorque manner with the planet gear enabling a rotational mounting of the planet gears within the planetary gearset.
Pretensioning bearing apparatuses by means of a pair of tapered roller bearings with the use of a lid-type construction and hex-head screws is known in the art. Further known in the art is a bearing apparatus with cylindrical roller bearings that are pretensioned with a hex-head screw, particularly to ensure the non-slip operation of the planetary gearset. However, the rotational tightening method that is typically employed in this context can result in imprecise pretensioning forces coupled with a relatively large dispersion of friction moments below a screw-head contact surface. In addition, such pretensioning is usually associated with minimal clamping length of the screws, thus creating the risk that the pretension may come loose and is only of very limited robustness relative to torsional deformations of the planetary carrier.
The bearing apparatus with its roller bearings is a very sensitive piece of machinery; the pretensioning of the bearings must be adjusted very precisely and permanently maintained to guarantee the reliability of the planetary gearset for the duration of the required operating life thereof.